Above: Supporters of Yes! For A Better San Diego gathered to announce an endorsement from the San Diego Police Officer's Association at a Father Joe's facility in downtown Monday, Feb. 5, 2018.

The organizers of a proposed ballot measure that would raise money for the downtown convention center and homelessness programs launched their signature-gathering effort Monday.

The Yes! For a Better San Diego campaign proposes a 42-year increase in the city's visitor tax that they say would generate $3.78 billion to expand and update the convention center, $2.02 billion for homeless services and $604 million for street repairs over the life of the measure.

They must gather 71,000 signatures for the issue to appear on the November ballot.

If approved by voters, the measure would increase the visitor tax on hotel bills by 1.25 percent to 3.25 percent. Hotels closest to the convention center would see the largest hike.

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During the first years of the tax increase, 59 percent of revenues would go toward the convention center and 41 percent to homelessness programs. Between 2025 and 2061, 59 percent would go toward the center, 31 percent to homelessness programs and 10 percent to city street repairs.

The San Diego Police Officers Association endorsed the plan at a news conference Monday that kicked off the signature gathering.

Other supporters include hospitality industry leaders, Mayor Kevin Faulconer, Father Joe Carroll and deacon Jim Vargas of Father Joe's Villages, Bob McElroy of the Alpha Project and the San Diego and Imperial Counties Labor Council. They say the measure would offer long-term solutions to some of the city's most vexing problems.

The campaign says the upgrades to and expansion of the convention center would generate $40 billion in economic activity over the life of the measure and create about 7,000 jobs.

The City Council is considering another ballot question proposed by Councilman David Alvarez that would earmark existing hotel tax revenue exclusively for homelessness prevention and housing programs.